2-Amino-3-cyano-5-(2-fluorophenyl)-4-methylpyrrole is known to be an excellent therapeutic drug for treating pollakiuria and urinary incontinence having a bladder-selective calcium-sensitive potassium channel activating effect (see PCT WO99/36068).
On the other hand, the above described drug was found to have a short plasma half life, which may cause nocturnal pollakiuria or urinary incontinence, due to which a patient is forced to dose the drug at night, resulting in a problematic reduction in the QOL (quality of life) or the compliance of the patient.